Watch CloudFormation Events during `aws cloudformation deploy`

aws-cloudformation-deploy-watcher.sh

#!/usr/bin/env bash
set -o errexit  # exit when a command line fails
set -o pipefail # pipes exit code will be the last non-zero exit code of all pipe commands
set -o nounset  # exit on read a undeclared variable
#set -o xtrace   # enable debug logging

#### Source: https://gist.github.com/qoomon/d6633abe35eea297f475260478f86c8c 

### Usage ###
#
# aws cloudformation deploy --stack-name "$STACK_NAME" ... \
#   | ./aws-cloudformation-deploy-watcher.sh --stack-name "$STACK_NAME" ...
#
#############

WATCH_TIMEOUT=$(( 60 * 15 )) # in seconds
WATCH_INTERVAL=2              # in seconds

function echo_help {
  echo "usage: $0 [options]"
  echo ""
  echo "example: aws cloudformation deploy ... | $0 [options]"
  echo ""
  echo "options:"
  echo "  --stack-name"
  echo "  --profile"
  echo "  --region"
  echo "  --help"
}

function reverse { sed '1!G;h;$!d'; }

while [[ $# -gt 0 ]]
do
  case $1 in
    --stack-name) opt_stack_name="$2"; shift 2;;
    --profile)    opt_profile="$2"; shift 2;;
    --region)     opt_region="$2"; shift 2;;
    --help)       echo_help; exit 0;;
    *)
      >&2 echo "[ERROR] unexpected argument: $1"
      >&2 echo_help
      exit 1;;
  esac
done

if [[ ! "${opt_stack_name:-}" ]]
then
  >&2 echo "[ERROR] '--stack-name' parameter missing"
  >&2 echo_help
  exit 1
fi

while read -r line
do
    echo "${line}"
    if [[ "${line}" = "Waiting for stack create/update to complete" ]]
    then
        echo
        start_watch_time=$(date +%s)
        while [[ $(( $(date +%s) - $start_watch_time )) -lt WATCH_TIMEOUT ]]
        do
            sleep $WATCH_INTERVAL

            prior_deploy_events="${recent_deploy_events:-}"

            # get recent stack events since last 'User Initiated' change
            recent_deploy_events="$(aws cloudformation describe-stack-events --stack-name "${opt_stack_name}" \
                ${opt_profile:+ --profile "${opt_profile}"} \
                ${opt_region:+ --region "${opt_region}"} \
                --query 'StackEvents[*].[Timestamp,ResourceType,LogicalResourceId,ResourceStatus,ResourceStatusReason]' --output text \
                | awk "NR==1,/\tAWS::CloudFormation::Stack\t${opt_stack_name}\t.*\tUser Initiated\$/" \
                | reverse)"

            # determine new events
            new_deploy_events="$(comm -13 <(echo "${prior_deploy_events}") <(echo "${recent_deploy_events}"))"

            if [ -n "$new_deploy_events" ]
            then
              printf '\r'
              # print new event
              echo "${new_deploy_events}" \
                  | awk -F '\t' '{printf "%s   %-32s   %-32s   %-24s   %s\n",$1,$2,$3,$4,$5}' \
                  | sed 's/None$//'

              TAB_CHAR=$'\t'

              # check for final ERROR state
              if (echo "${new_deploy_events}" | grep -q "AWS::CloudFormation::Stack${TAB_CHAR}${opt_stack_name}${TAB_CHAR}.*\(_ROLLBACK_COMPLETE|_FAILED\)${TAB_CHAR}")
              then
                  exit_code=1
                  break
              fi

              # check for final Success state
              if (echo "${new_deploy_events}" | grep -q "AWS::CloudFormation::Stack${TAB_CHAR}${opt_stack_name}${TAB_CHAR}.*\(_COMPLETE\)${TAB_CHAR}")
              then
                  exit_code=0
                  break
              fi
            else
              printf '.'
            fi
        done
        echo
    fi
done

exit ${exit_code:-0}